Gymnosperm
Gymnosperms are seed-bearing, vascular plants. The term gymnosperm comes from the Greek word gumnospermos meaning literally "naked seed". This term is applied because the seeds of these plants are not formed in an enclosed ovulary (pistil with one or more carpels, developing into a fruit as in the angiosperms), but naked on the scales of a cone-like structure. At one time, gymnosperm was a class (Class Gymnospermae), first within the seed plants (Division Spermatophyta; 1883~1950), later within the vascular plants (Division Tracheophyta; 1950~1981), and essentially encompassing the conifers and their allies (by which is meant "related species of plants" and including several groups of extinct plants known from fossils). These plants were set off from the other classes of higher plants that recognized the ferns and flowering plants. In the modern classification, the gymnosperms in a stricter sense have been elevated to the Division Pinophyta, with the formerly included Gnetales, Ginkgoales, and Cycadales (the "allied" groups) now given equal rank as Division Gnetophyta, Division Ginkgophyta, and Division Cycadophyta — see Kingdom Plantae.
Examples of gymnosperms include cypress, juniper, and — most well known — pine, fir, and redwood. Included in this group are the tallest trees, Giant sequoia, and the world's oldest living trees, the Bristlecone pines that grow only on the North American contintent.
Referenced By
Cork cambium | Cotyledon | Evolutionary timeline | Leyland cypress | Leylandii | Timeline of evolution | Vascular cambium
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